Cable modems provide customers with high-speed access to networks, such as the Internet. Generally, the typical cable modem user is a home user, desiring connection to the Internet. However, many small businesses are discovering that cable modems provide them with a reasonable solution for Internet access. Some small businesses have even begun to deploy voice data over cable modems as an alternative to dedicated telephone lines.
Cable modems connect to a network through a Cable Modem Termination Server (CMTS). This provides connection to the Internet, and switching and routing of data packets. For a small business that only has one office, a single cable modem may be able to provide service for the entire office, through one CMTS.
If a small business has more than one office, and each office has its own cable modem, there may be more than one CMTS involved in providing network services to the business. For small business desiring ‘layer 2’ local area network (LAN) services, this causes problems. The CMTS may be able to provide ‘layer 3’ services for the individual cable modems, but not layer 2 services. These may include, but are not limited to, support for non-Internet Protocol (IP) version 4 protocols (currently provided by layer 3 services), end-to-end encryption, higher levels of network control, and use of a private IP address space.